This invention relates to improvements in reciprocable pumps, particularly oil well service pumps.
In conventional well service pumps it is difficult to detach the fluid end from the power frame in order to replace it or make repairs. Normally, a close fitting pilot is provided for mounting of the fluid end in properly centered alignment in the frame with respect to the plunger. Threaded fasteners are used to secure the fluid end to the pilot and frame. The pilot and fasteners often become corroded and get stuck. Therefore, detachment of the fluid end may be difficult and time-consuming. Recently, sectional fluid ends have been provided so that, for example, only a plunger bore portion of the fluid end need be changed to replace packing or change pump capacity, an example is shown in U.S. Pat. No. 3,801,234, Love et al. These designs however still utilize threaded fasteners for attaching the parts to the frame thus not alleviating the problems encountered in disassembly.
One of the advantages of sectional designs is that the size of the fluid end body may be reduced, thus decreasing cost. This concept can be carried even further by providing suction and discharge passages which join the plunger passage at equal angles, preferably at 120 degrees with respect thereto so as to minimize stresses. However, this configuration normally requires that the suction and discharge passages by tilted away from a vertical alignment. Thus, valve wear tends to increase.
Another feature of some sectional pumps is that the valve covers may be readily detachable so that repair or replacement is easier. However, in large pumps manual handling of the parts is difficult and perhaps even hazardous.
It is a primary object of this invention to provide various improvements in reciprocable pumps for decreasing the time required for disassembly and replacement or repair, as well as making handling of the parts easier.
It is another object of this invention to decrease valve wear in a fluid end having suction or discharge passages which are displaced from vertical alignment.